Need help in ssh key authentication

[$t!$-]

Hii Guys,
I wan to make a passwordless connection between windows and HPUX machine. On HPUX machine i am using openssh and windows i have installed sshd server. Then i have creatd public and private key pair using puttygen and placed a public key under HPUX $HOME/.ssh/ directory with right permissions. When i connect to HP server using putty ,it allows me after entering password. When i try with ssh key it gives me error that..
............
Server refused our key
Using keyboard-interactive authentication.
Password:
...............
I am thinking that key generated by puttygen is not acceptable by HP unix server??. can any one suggest me any way to make compatible or anyother way to generate public and private key on windows machine?

I have tried reverse connection also,that is also not working with key.With passwrod that is also working.